1. Field of the Invention
The present general inventive concept relates to a toner cartridge to supply toner to an electrophotographic printer to contribute to development, and an electrophotographic printer employing the same, and more particularly, to a horizontal installation type fixed toner cartridge in which a specification of the toner cartridge, the arrangement and specification of the toner cartridge with respect to a photoreceptor drum, and specifications of the photoreceptor drum and a development roller are optimized, and an electrophotographic printer employing the same.
2. Description of the Related Art
In general, electrophotographic printers form an electrostatic latent image by scanning light onto a photosensitive medium to charge to a predetermined electric potential, and the electrostatic latent image is developed by a predetermined color toner. The developed image is transferred to a print paper and fused thereon so that an image is printed.
The electrophotographic printer can be divided into a wet type electrophotographic printer and a dry type electrophotographic printer according to a developer. The wet type electrophotographic printer uses a developer made by mixing a liquid carrier and toner powder. The dry type electrophotographic printer uses a dual component developer made by mixing a powder carrier and a toner or a single component developer excluding carrier.
Also, the electrophotographic printer can be divided into a black and white printer and a color printer according to the presence of realization of color. The black and white printer uses a single toner cartridge having a black color. The color printer uses four toner cartridges having yellow, magenta, cyan, and black colors to supply toner and perform development. Also, the color printer can be divided into a single pass type color printer and a multi-pass type color printer according to a color image realization manner.
The single pass type color printer adopts exposure units and chargers corresponding to four color development units with respect to a single photosensitive medium. The single pass type color printer prints a color image by one turn of the photosensitive medium. Thus, for color printing, a high speed printing is possible at the same speed as that for printing a mono color image. However, by adopting a plurality of exposure units and chargers, a structure of the single pass type color printer becomes complicated, and a manufacturing cost increases.
The multi-pass type color printer adopts a single exposure unit and a single charger and four development units for developing each color. The multi-pass type color printer prints a full color image by four turns of the photosensitive medium. Accordingly, a print time is theoretically four times longer than that of the single pass type color printer. However, since the single exposure unit and the single charger are employed, a structure of the printer becomes simplified, and a manufacturing cost is reduced.
The above descriptions are disclosed in U.S. patent application Ser. No. 10/620,768, entitled a color image forming apparatus and a color image forming method and filed on Jul. 17, 2003 by the present applicants and in U.S. patent application Ser. No. 10/822,004, entitled an electrophotographic printer and filed on Apr. 12, 2004 by the present applicants.
The electrophotographic printer adopts a multi-pass type. In a structure of the electrophotographic printer, a toner cartridge corresponding to each color is horizontally installed with respect to a printer main body and is fixed with respect to the printer main body during printing.
In this structure, a plurality of toner cartridges contributing to development are fixed in the electrophotographic printer. Thus, compared to a printer adopting a conventional toner cartridge, noise and vibration generated during its operation can be fundamentally removed. Also, by omitting a structure to slide or rotate a development unit, the structure thereof can be simplified and a manufacturing cost can be reduced.
In the meantime, in a printer adopting a horizontal installation type fixed toner cartridge, considering a print quality improvement, a compact structure, a reduction of an assembly step, and a reduction of a manufacturing cost, it is required to optimize a height of each toner cartridge, a total effective height of the entire toner cartridges, an opening angle of a development roller, and the specification of the photosensitive medium into values within a predetermined range. Furthermore, it is required to specify the arrangement structure of the toner cartridges.